1. Field of the Invention
The present invention relates to the light-sensing field, and specifically, to a mixed multi-spectrum light-sensing pixel group, a light-sensing device, and a light-sensing system.
2. Related Art
The present invention is continuation to “multi-spectrum light-sensing device and manufacturing method for same” (PCT/CN2007/071262), “multi-spectrum light-sensing device and manufacturing method for same” (Chinese Application No: 200810217270.2), “multi-spectrum light-sensing device” (Chinese Application No: 200910105372.X), “multi-spectrum light-sensing device and sampling method for same” (Chinese Application No: 200910105948.2), and “light-sensing device and reading method for same, and reading circuit” (Chinese Application No: 200910106477.7) applied by the inventor at an earlier time, aiming to provide more specific and preferable implementation at a chip and system grade.
The present inventions listed above mainly relate to a method and a system for manufacturing and reading a multi-spectrum light-sensing chip with a semiconductor as a main body. These new technologies and inventions enormously improve performances and application manners of a semiconductor light-sensing device, but are still subjected to two basic limitations of the semiconductor light-sensing device itself: (1) the bandgap is small, so that infrared induction is greatly limited; and (2) the semiconductor quantum efficiency is only about 50%.
Recently, U.S. patent application entitled “Materials, Systems and Methods for Optoelectronic Devices” (PCT/US2008/060947, WO2008/131313) proposes a method for manufacturing a light-sensing pixel by use of a quantum (light-sensing) film formed of quantum dots (as shown in FIG. 1 to FIG. 4). In the application, a quantum coating which is more sensitive to a light signal and whose bandgap is wider is invented, where the character that the magnitude of the quantum dot size (namely, quantum dot diameter) has a frequency selection characteristic is utilized to implement induction of different colors, and this quantum coating is capable of providing higher photoelectric conversion efficiency, and capable of providing a wider-frequency-spectrum response characteristic (as shown in FIG. 5). The quantum dot light-sensing pixel mentioned in the application is actually a special case of a more generalized chemical coating light-sensing pixel, and the idea adopted for the chemical coating light-sensing pixel is as follows: basically a bias voltage is applied on a chemical coating, then free electrons (or holes) are induced by light illumination to run away, and the free electrons (or holes) are induced to the surface layer of the coating by the bias voltage to accumulate charges, thereby implementing photosensitivity. By means of the present invention, a light filtering film and an additional semiconductor reading layer are required, while the light-sensing efficiency of the chemical coating light-sensing device is limited due to use of the light filtering film.
Therefore, there is a more advanced preferable implementation method, so as to obtain better light-sensing effect. For example, when multi-spectrum light-sensing is performed, there is still an improvement space for how to better give consideration to demands for both color and sensitivity, and how to approximate to or achieve the ideal orthogonal characteristic required by the color light-sensing device (as response curves of red, green, and blue shown in FIG. 6) so as to have the highest photoelectric conversion efficiency simultaneously.